Diversity of anammox bacteria and abundance of functional genes for nitrogen cycling in the rhizosphere of submerged macrophytes in a freshwater lake in summer
Purpose Submerged plants make an important contribution to nitrogen cycling in lakes including in the rhizosphere microenvironment through microbial activities. The main objective of this study was to investigate the abundance of functional genes for nitrogen cycling and the ecological relationship...
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Published in | Journal of soils and sediments Vol. 19; no. 10; pp. 3648 - 3656 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
01.10.2019
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | Purpose
Submerged plants make an important contribution to nitrogen cycling in lakes including in the rhizosphere microenvironment through microbial activities. The main objective of this study was to investigate the abundance of functional genes for nitrogen cycling and the ecological relationship between these genes in the rhizosphere sediment of a freshwater lake in summer.
Materials and methods
Sediment from the rhizosphere of four submerged macrophytes (
Ceratophyllum demersum
,
Hydrilla verticillata
,
Potamogeton maackianus
, and
Vallisneria spiralis
) was sampled in Lake Liangzi, China, in summer. The anammox bacteria community structure and abundance of five functional genes for nitrogen cycling, ammonia monooxygenase (
amoA
) of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), anammox 16S rRNA, and nitrite reductase genes (
nirK
and
nirS
) in the sampled sediment, were determined.
Results and discussion
A total of 100 anammox gene sequences were grouped into eight operational taxonomic units (OTUs) and genus Ca.
Kuenenia
was the dominant species in Lake Liangzi in summer. Quantitative polymerase chain reaction (qPCR) revealed that gene copies of AOA
amoA
(2.42 × 10
6
copies g
−1
) were more than one order of magnitude higher than those of AOB
amoA
(1.98 × 10
5
copies g
−1
). The
nirS
gene (4.13 × 10
8
copies g
−1
) was more abundant than the
nirK
gene (7.28 × 10
7
copies g
−1
). There was no significant difference in the abundance of the AOB
amoA
gene among the rhizosphere of the four macrophytes. Redundancy analysis (RDA) showed a positive correlation between the abundance of the anammox 16S rRNA gene, AOA
amoA
and AOB
amoA
, which suggested two of these microbes may have provided a substrate for anammox bacteria in summer.
Conclusions
The diversity of anammox in the rhizosphere of submerged macrophytes of the freshwater lake in summer was very low, but the plant species could affect the abundance of most nitrogen circulating bacteria, especially for anammox bacteria. Anammox 16S rRNA gene was positively correlated with four other functional genes, indicating that all four genes had significant effects on anammox bacteria. |
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ISSN: | 1439-0108 1614-7480 |
DOI: | 10.1007/s11368-019-02340-4 |